Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using a partially purified enzyme preparation obtained from hamster epididymis, a simple assay has been developed to measure the sulfurylation of dehydroisoandrosterone (DHA) and desmosterol in the presence of 3'-phosphoadenosine 5'-phospho[35S]sulfate [( 35S]PAPS). After stopping the enzymatic reaction with methanol and KCl, the 35S-labelled steroid sulfates are readily extracted into an organic phase. Optimal conditions for the sulfurylation of the two steroids were compared; optimum pH is 8.7 for DHA and 9.8 for desmosterol. Sulfoconjugation of desmosterol increases with magnesium concentrations up to 6 mM, while 40 mM concentrations of the divalent ion are required for the optimal sulfurylation of DHA. Maximum sulfurylation of these steroids requires the presence of 15 mM cysteine. Michaelis-Menten kinetics are observed with DHA which has an apparent Km of 32 microM, while desmosterol inhibits sulfotransferase activity at high concentrations. Saturation of the enzyme with PAPS results in an allosteric behaviour. Only the 3 beta-hydroxyl function of the steroid nucleus appears to be an appropriate sulfate acceptor for the epididymal hydroxysteroid sulfotransferase.
 ...
PMID:The assay and partial characterization of 3 beta-hydroxysteroid sulfotransferase of the hamster epididymis. 315 30

Steroid sulfotransferase activity has been assayed in cytosol extracts obtained from the male hamster reproductive tract. Dehydroisoandrosterone and desmosterol were used as substrates in the presence of phosphoadenosine phosphosulfate-35S as sulfate donor. No significant sulfotransferase activity was found in the testis. In the epididymis, a severalfold increase in activity was found in the tissue from the caput to the caudal regions. A lower but significant activity was detected in the vas deferens. The enzyme appears to be secreted into the luminal fluid while little activity is associated with the spermatozoa. This increase in activity along the epididymis is undoubtedly responsible for the accumulation of sterol sulfates reported previously. In view of the fact that sterol sulfates are potent and specific inhibitors of acrosin, as reported for the porcine and confirmed herein for hamster acrosin, the epididymal production of steroid and sterol sulfates may represent a protective mechanism against the premature release of proteolytic activity within the male reproductive tract.
 ...
PMID:Distribution of steroid sulfotransferase in the male hamster reproductive tract. 624 Feb 84

Epididymis provides a safe environment in which stored-spermatozoa could survive for days before ejaculation. In vitro studies suggested that epididymal proteins seem to be implicated in sperm survival during coincubation with cultured epididymal cells. This study was basically designed to confirm if secretory proteins from bovine epididymal cell cultures provide sperm protection against rapid loss of sperm motility in vitro. Bovine spermatozoa were incubated in conditioned media (CM), which were prepared from cultured cauda epididymal cell (CEC). Motion parameters were recorded using a computer-assisted sperm analyzer. Sperm-free protein extracts from CM were fractionated by ultrafiltration through a 10-kDa cut off membrane. A significantly positive effect on sperm motility was observed when spermatozoa were incubated in CM (54 +/- 4%) and CM > 10 kDa (57 +/- 4%) compared to CM < 10-kDa fraction (30 +/- 3%) or fresh media (34 +/- 3%), after a 6-hr incubation period. This beneficial effect on sperm motility was abolished when the CM > 10-kDa fraction was heat-treated at 100 degrees C for 10 min. The CM > 10 kDa fraction provides factors that remained active even though spermatozoa were washed twice after a 2-hr preincubation period. To identify potential beneficial factors, bovine spermatozoa were incubated with radiolabeled proteins obtained using (35)S-methionine in culture medium. SDS-PAGE analysis of proteins extracted from CM-preincubated spermatozoa revealed the presence of a 42-kDa protein strongly associated to the sperm surface. This 42-kDa spot was trypsin-digested and identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) as a protein homologue to a 35-kDa bovine estrogen-sulfotransferase. This protein can play a role in epididymal biology and sperm function. Taken together, these results suggest that specific epididymal proteins can be implicated in the sperm protection in vitro, and can be characterized in our cell culture system.
 ...
PMID:Characterization of secretory proteins from cultured cauda epididymal cells that significantly sustain bovine sperm motility in vitro. 1241 53

The carboxylic antibiotic ionophore monensin is well-known for the Na+/H+ exchanger activity across the biological membranes. The current study has been designed to investigate the effect of monensin on spermatozoal concentration, motility, and oxidative stress-related parameters in the rat epididymis. Monensin was administered orally at a dose of 3.5 mg/kg body weight daily for 70 days, a duration that coincides with the completion of the spermatogenic cycle. At the end of the respective treatment, the epididymis was isolated into three separate regions--the capitum, corpus, and the cauda--successively away from the head of the testis. Marked changes were noted in the body weight, organ (epididymis) weight, sperm concentration and motility, as well as the morphologic observations of the sperm and the histologic architecture of the epididymal epithelium. Significant alterations were also recorded in the oxidative stress parameters such as the lipid peroxidation product, malonyldialdehyde, and the activity of superoxide dismutase, glutathione sulfotransferase, glutathione reductase, and catalase. The nonenzymatic thiol content such as the total, oxidized, and reduced glutathione showed significant changes and the tissue phosphatases such as alkaline and acid phosphatase were increased, indicative of the interference of the drug in lysosomal and Golgi membrane complex. The findings of the current study indicate interactions during the spermatozoal maturational process in the epididymis, and a significant potential use of monensin in male contraception may be suggested.
 ...
PMID:Oxidative effects of Na+--specific ionophore monensin on the rat epididymis. 1793 28

Boars exhibit high concentrations of sulfonated estrogens (SE) mainly originating from the testicular-epididymal compartment. Intriguingly, in porcine Leydig cells, sulfonation of estrogens is colocalized with aromatase and steroid sulfatase (STS), indicating that de novo synthesis of unconjugated estrogens (UE), their sulfonation and hydrolysis of SE occur within the same cell type. So far in boars no plausible concept concerning the role of SE has been put forward. To obtain new information on SE formation and hydrolysis, the porcine testicular-epididymal compartment was screened for the expression of the estrogen-specific sulfotransferase SULT1E1 and STS applying real-time RT-qPCR, Western blot and immunohistochemistry. The epididymal head was identified as the major site of SULT1E1 expression, whereas in the testis, it was virtually undetectable. However, SE tissue concentrations are clearly consistent with the testis as the predominant site of estrogen sulfonation. Results from measurements of estrogen sulfotransferase activity indicate that in the epididymis, SULT1E1 is the relevant enzyme, whereas in the testis, estrogens are sulfonated by a different sulfotransferase with a considerably lower affinity. STS expression and activity was high in the testis (Leydig cells, rete testis epithelium) but also present throughout the epididymis. In the epididymis, SULT1E1 and STS were colocalized in the ductal epithelium, and there was evidence for their apocrine secretion into the ductal lumen. The results suggest that in porcine Leydig cells, SE may be produced as a reservoir to support the levels of bioactive UE via the sulfatase pathway during periods of low activity of the pulsatile testicular steroidogenesis.
 ...
PMID:SULFATION PATHWAYS: Formation and hydrolysis of sulfonated estrogens in the porcine testis and epididymis. 2946 39